Kinetic simulations of X-B and O-X-B mode conversion

We have performed fully-kinetic simulations of X-B and O-X-B mode conversion in one and two dimensional setups using the PIC code EPOCH. We have recovered the linear dispersion relation for electron Bernstein waves by employing relatively low amplitude incoming waves. The setups presented here can be used to study non-linear regimes of X-B and O-X-B mode conversion.Comment: 4 pages, 3 figure

Fatalities involving illicit drug use in Pretoria, South Africa, for the period 2003 - 2012

Background. Globally, illicit drugs are responsible for many fatalities annually, yet accurate data on the nature and extent of these deaths in South Africa (SA) are lacking.Objectives. To investigate the presence and profile of illicit drugs detected in deceased persons who were subjected to medicolegal autopsies and upon whom analyses were carried out in search of illicit drugs in their body fluids at the Pretoria Medico-Legal Laboratory (PMLL), SA, over a 10-year period.Methods. A retrospective descriptive case audit was conducted for the period 2003 - 2012.Results. Screening for illicit drugs was requested in 385 out of 22 566 medicolegal autopsies. Results were available for only 281 of these cases, with 154 cases showing the presence of one or more illicit drugs. The demographic profile of positive cases indicated the majority to be male (90.3%) and white (85.1%). Decedents who tested positive for illicit drugs were predominantly aged between 20 and 30 years (51.9%). The most frequently detected drug was heroin, the presence of which was confirmed in 35.2% of cases, followed by cocaine in 19.9%. Alcohol in combination with an illicit drug or drugs was detected in 56 cases (36.4%).Conclusions. Results from this study indicate that illicit drugs were implicated in a considerable number of fatalities in Pretoria. However, it is believed that the figures are a gross under-representation of the actual number of drug users who died during this period. It is therefore recommended that further research be conducted and that drug screening be requested routinely when unnatural deaths are investigated at medicolegal mortuaries, not only to ensure the administration of justice but also to obtain more accurate data for purposes of public health programmes and improve insight into the burden of illicit drug use in SA

The Effect of Grape Temperature on the Sensory Perception of Méthode Cap Classique Wines

The production process of South African bottle-fermented sparkling wine, the Méthode Cap Classique (MCC), follows the traditional French method (méthode champenoise), although each cellar has its own unique additions to the method. South African winemakers use different techniques and blends to achieve their award-winning MCCs, but there have not been many scientific investigations of the science behind these wines. This project is one of the first scientific studies on MCC. MCC wines were made using Chardonnay and Pinot Noir grapes harvested over two vintages (2014 and 2015) from two regions (Robertson and Darling) and stored at 0°C, 10°C, 25°C and 30°C before processing. The study was aimed at investigating the effect of grape storage temperature on the sensory characteristics of MCCs. The aroma and taste of the final nine-month old MCCs were evaluated, with each region analysed separately. The study showed a grouping of the MCCs according to temperature treatments for both vintages. There werevintage differences in terms of the attributes cited and the frequency of citations. Based on the frequency of citation, the MCCs made 2014 from grapes stored at 0°C and 10°C were described by the judges as having a fruity, fresh and crisp aroma, whilst those made from grapes stored at 25°C and 30°C were described as having oxidised fruit, volatile acidity and solvent-like aromas. The judges perceived less oxidation and volatile acidity (VA) (in terms of the frequency of citation) in the aroma of the 2015 MCCs, although treatments at higher temperatures were still associated with less desirable attributes compared to treatments at lower temperature. This study shown that the temperature of the grape at the time ofprocessing has a significant effect on the aroma of MCCs aged nine months, and not so much of an effect on the taste

Effect of Skin Contact Before and During Alcoholic Fermentation on the Chemical and Sensory Profile of South African Chenin Blanc White Wines

The volatile and phenolic composition of Chenin blanc wines made with different skin contact treatmentswas studied. One batch of grapes was used to make a dry white wine according to two different treatments,namely pre-fermentative skin contact and complete fermentation on the skins. A white wine fermentedwithout any skin contact was used as control. Fermentation on the skins and skin contact beforefermentation led to significantly lower levels of terpenes, esters, acids and thiols, and the highest significantlevels of alcohols and phenolic compounds. However, this effect was less pronounced in wines with skincontact before fermentation. Sensory analysis of all the experimental wines was also performed. The resultsshowed a significant shift from the sensory attributes of fresh and tropical fruits of the control Cheninblanc wines towards riper fruit notes in the skin contact treatments. This observation was correlated withthe length of the skin contact period. Possible reasons to explain the results observed in this study arediscussed

A comparative study on the efficiency of water soluble phosphates and a dry phosphate lick for sheep fed on mature grass hay

In a study with adolescent Merino sheep on a diet of mature grass hay, the supplementation with phosphates alone, either in the drinking water or as a dry lick, did not prevent loss of condition. Furthermore, in metabolism studies the phosphorus and nitrogen balances under these conditions were negative. However, the daily inclusion of small allowances of lucerne hay and maize samp to the diet resulted in increased intakes of protein and carbohydrate and ensured positive metabolism balances for phosphorus and nitrogen. Under these improved feeding conditions body weights increased. The result of feeding this diet suggested that phosphate feeding at certain times may be unnecessary under practical conditions.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format..mn201

SWIRP (Submm-Wave and Long Wave InfraRed Polarimeter); Development and Characterization of a Sub-Mm Polarimeter for Ice Cloud Investigations

A major source of uncertainty in climate models is the presence, shape and distribution of ice particles in the uppermost layers of the clouds. The effects of this component are poorly constrained, turning ice particles into an almost-free variable in many climate models.NASA-GSFC is developing a new instrument aimed at measuring the size and shape of ice particles. The instrument consists of two sub-mm polarimeters (at 220 and 670 GHz) coupled with a long-wave infrared polarimeter at 10 micron. Each polarimeter has identical V-pol and H-pol channels; the axes of polarization are defined geometrically by the orientation of the waveguide elements, and the purity has been measured in the lab. The instrument is configured as a conical scanner, suitable for deployment as a payload on a small satellite or on a high-altitude sub-orbital platform. From a 400 km orbit, the instrument has a 3dB spatial resolution of 20 (10) km at 220 (670) GHz and a swath of 600 km over 180 degrees of view.The BAPTA (Bearing And Power Transfer Assembly) carries heritage from the SSMIS design, now in its 22nd year of on-orbit operation, but with a much reduced SWaP (Size Weight and Power) footprint, suitable for a small satellite.The main components of the instrument have been fabricated and are undergoing final testing prior to their integration as a single unit. The sub-mm channels have dedicated secondary reflectors which illuminate a shared primary reflector. The receiving units are placed behind the focal point of the optical arrangement, so that all beams equally illuminate the primary reflector and are almost co-located on the ground (within a single 220 GHz footprint). Primary and secondary beam patterns have been measured and verified to match the as-designed expectations. A Zytex (TM) window is deployed to protect the secondary reflectors and the feed horns from debris and other contaminants, and to reduce the heat load from the active (hot) IR calibration unit. The insertion loss of Zytex has been measured and is accounted in the calibration equation of the sub-mm channels.The radiometric performance of the sub-mm receivers has been characterized in the lab and under operational conditions of temperature and pressure.This paper discusses the design constraints on the sub-mm components, details of the scientific goals and their flowdown, and describes the characterization of the polarimeters. Options to optimize the layout and distribution of the masses within the assembly, with the goal of making the instrument even more compact and fully-compatible with cubesat-class satellites will be presented

Fatalities involving illicit drug use in Pretoria, South Africa, for the period 2003 - 2012

Background. Globally, illicit drugs are responsible for many fatalities annually, yet accurate data on the nature and extent of these deaths in South Africa (SA) are lacking.Objectives. To investigate the presence and profile of illicit drugs detected in deceased persons who were subjected to medicolegal autopsies and upon whom analyses were carried out in search of illicit drugs in their body fluids at the Pretoria Medico-Legal Laboratory (PMLL), SA, over a 10-year period.Methods. A retrospective descriptive case audit was conducted for the period 2003 - 2012.Results. Screening for illicit drugs was requested in 385 out of 22 566 medicolegal autopsies. Results were available for only 281 of these cases, with 154 cases showing the presence of one or more illicit drugs. The demographic profile of positive cases indicated the majority to be male (90.3%) and white (85.1%). Decedents who tested positive for illicit drugs were predominantly aged between 20 and 30 years (51.9%). The most frequently detected drug was heroin, the presence of which was confirmed in 35.2% of cases, followed by cocaine in 19.9%. Alcohol in combination with an illicit drug or drugs was detected in 56 cases (36.4%).Conclusions. Results from this study indicate that illicit drugs were implicated in a considerable number of fatalities in Pretoria. However, it is believed that the figures are a gross under-representation of the actual number of drug users who died during this period. It is therefore recommended that further research be conducted and that drug screening be requested routinely when unnatural deaths are investigated at medicolegal mortuaries, not only to ensure the administration of justice but also to obtain more accurate data for purposes of public health programmes and improve insight into the burden of illicit drug use in SA

Intra-uterine foetal blood transfusion

No Abstract

The bottom line : tailoring a public health elective to students’ needs

CONTEXT AND SETTING: Academics face difficulties when trying to include public health in the medical curriculum. The first hurdle is an already overloaded curriculum and the second the marginal interest in the healthy on the part of those who are mainly concerned with the ill. One overlooked potential opportunity for inclusion in the curriculum is the elective and, in particular, the self-constructed elective of third-year medical students at the University of Pretoria. WHY THE IDEA WAS NECESSARY Not only does public health have to compete with the powerful clinical interests among students, but students are also not in a position to identify opportunities in the community that could offer meaningful learning opportunities for an elective in public health. WHAT WAS DONE: An action research study design used an online survey to explore the factors that students take into account when constructing an elective experience. These factors determined the final design of a public health elective which was subsequently advertised to third-year medical students at the University of Pretoria as a possible option. RESULTS AND IMPACT: Disappointingly, no student enrolled for the elective. Subsequent investigation of students’ actual choices resulted in a deeper understanding of students’ unvoiced needs. It would appear that a successful public health elective needs to be like a mini-skirt − long enough to cover the subject, but short enough to hold interest. Academics considering innovations in public health could benefit from this complexity in design.This project forms part of the requirement of the Southern African FAIMER Regional Institute fellowship programme.http://www.ajhpe.org.za/index.php/ajhpeam201